bpo-37741: make importlib.metadata docs discoverable through a module directive. (GH-25415)

Automerge-Triggered-By: GH:jaraco

Author: jaraco

Doc/library/importlib.metadata.rst

@@ -4,6 +4,11 @@
  Using :mod:`!importlib.metadata`
 =================================
 
+.. module:: importlib.metadata
+   :synopsis: The implementation of the importlib metadata.
+
+**Source code:** :source:`Lib/importlib/metadata.py`
+
 .. note::
    This functionality is provisional and may deviate from the usual
    version semantics of the standard library.